North American hard yellow liver disease: an old problem readdressed

Authors: Stegelmeier, Bryan; JONES, MEREDYTH - Oklahoma State University; WOMACK, CHRISTOPHER - Los Caballos Veterinary Clinic; Davis, Thomas - Zane; Gardner, Dale

Submitted to: Poisonous Plant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2019
Publication Date: 10/23/2019
Citation: Stegelmeier, B.L., Jones, M., Womack, C.P., Davis, T.Z., Gardner, D.R. 2019. North American hard yellow liver disease: an old problem readdressed. Poisonous Plant Research. 2:1-13. https://doi.org/10.26077/6ksg-1685.
DOI: https://doi.org/10.26077/6ksg-1685

Interpretive Summary: Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn antelope (Antilocapra americana) and whitetail deer (Odocoileus virginianus texanus) within several Texas counties in the United States. Clinically it presents as chronic liver disease that results in livestock deaths or condemnation of all or part of the carcass if the affected animal is slaughtered. The cause of hard yellow liver disease has not been identified. The objectives for this study are to review more recent cases and compare these with historical reported cases. The bovine livers is this study had a spectrum of lesions including lipid degeneration and necrosis, eosinophilic granulomatous hepatitis, focal follicular lymphoid proliferation and chronic fibrosing hepatitis with dystrophic mineralization. No pyrrolizidine alkaloid metabolites were detected in any of the lesions and select special stains did not reveal any fungal, bacterial or parasitic etiologies. The lack of findings and mixed histologic presentation suggest that this syndrome is a collection of chronic diseases probably of various causes. More work is needed to better understand the cause and sporadic nature of this disease.

Technical Abstract: Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn antelope (Antilocapra americana) and whitetail deer (Odocoileus virginianus texanus) within several Texas counties in the United States. Clinically it presents as chronic liver disease with progressive hepatic necrosis and fibrosis, icterus and liver failure. The damaged livers are yellow and many have multiple focal firm, often gritty foci that are scattered throughout all lobes. Early investigations included feeding studies using potential toxic plants, climate and forage studies, infectious disease surveys and various mycotoxin studies and analyses. None have definitively reproduced the disease or identified the inciting cause. However, the problem continues and recent outbreaks have allowed the collection of additional frozen tissues, and numerous paraffin tissue blocks and slides for additional studies. The objectives for this work are to evaluate these additional cases and compare the microscopic changes, special histochemical studies, microbial and fungal surveys and chemical assays for pyrrolizidine alkaloid metabolites. Similar to previous studies these bovine livers had a spectrum of lesions including lipid degeneration and necrosis, eosinophilic granulomatous hepatitis, focal follicular lymphoid proliferation and chronic fibrosing hepatitis with dystrophic mineralization. No pyrrolizidine alkaloid metabolites were detected in any of the lesions and select special stains did not reveal any fungal, bacterial or parasitic etiologies. The lack of findings and mixed histologic presentation suggest that this syndrome is a collection of chronic diseases probably of various etiologies. More work is needed to better understand the etiology and pathogenesis of this syndrome.